package org.bjtu.hadooptest.hadoop;

import java.io.FileInputStream;
import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class CopyFromLocalFile {
    /**
     * 判断路径是否存在
     */
    public static boolean test(Configuration conf, String path) {
        try (FileSystem fs = FileSystem.get(conf)) {
            return fs.exists(new Path(path));
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 复制文件到指定路径 若路径已存在，则进行覆盖
     */
    public static void copyFromLocalFile(Configuration conf,
                                         String localFilePath, String remoteFilePath) {
        Path localPath = new Path(localFilePath);
        Path remotePath = new Path(remoteFilePath);
        try (FileSystem fs = FileSystem.get(conf)) {
           /* fs.copyFromLocalFile 第一个参数表示是否删除源文件，第二个参数表示是否覆盖 */
            fs.copyFromLocalFile(false, true, localPath, remotePath);
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    /**
     * 追加文件内容
     */
    public static void appendToFile(Configuration conf, String localFilePath,
                                    String remoteFilePath) {
        Path remotePath = new Path(remoteFilePath);
        try (FileSystem fs = FileSystem.get(conf);
             FileInputStream in = new FileInputStream(localFilePath);) {
            FSDataOutputStream out = fs.append(remotePath);
            byte[] data = new byte[1024];
            int read = -1;
            while ((read = in.read(data)) > 0) {
                out.write(data, 0, read);
            }
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 主函数
     */
    public static void main(String[] args) {
        Configuration conf = new Configuration();
        conf.set("fs.defaultFS", "hdfs://172.31.42.153:9000");
        String localFilePath = "E:/color100.txt"; // 本地路径
        String remoteFilePath = "/user/root/color100.txt"; // HDFS路径
        // String choice = "append"; // 若文件存在则追加到文件末尾
        String choice = "overwrite"; // 若文件存在则覆盖

        try {
           /* 判断文件是否存在 */
            boolean fileExists = false;
            if (CopyFromLocalFile.test(conf, remoteFilePath)) {
                fileExists = true;
                System.out.println(remoteFilePath + " 已存在.");
            } else {
                System.out.println(remoteFilePath + " 不存在.");
            }
           /* 进行处理 */
            if (!fileExists) { // 文件不存在，则上传
                CopyFromLocalFile.copyFromLocalFile(conf, localFilePath,
                        remoteFilePath);
                System.out.println(localFilePath + " 已上传至 " + remoteFilePath);
            } else if (choice.equals("overwrite")) { // 选择覆盖
                CopyFromLocalFile.copyFromLocalFile(conf, localFilePath,
                        remoteFilePath);
                System.out.println(localFilePath + " 已覆盖 " + remoteFilePath);
            } else if (choice.equals("append")) { // 选择追加
                CopyFromLocalFile.appendToFile(conf, localFilePath,
                        remoteFilePath);
                System.out.println(localFilePath + " 已追加至 " + remoteFilePath);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

//    作者：Tiny_16
//    链接：https://www.jianshu.com/p/0663d74b79b5
//    來源：简书
//    著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
}
